Acrylic AB and ABA block copolymers based on poly(2-ethylhexyl acrylate) (PEHA) and poly(methyl methacrylate) (PMMA) via ATRP

ACS Appl Mater Interfaces. 2012 Aug;4(8):4200-7. doi: 10.1021/am300915j. Epub 2012 Aug 10.

Abstract

Acrylic block copolymers have several advantages over conventional styrenic block copolymers, because of the presence of a saturated backbone and polar pendant groups. This investigation reports the preparation and characterization of di- and triblock copolymers (AB and ABA types) of 2-ethylhexyl acrylate (EHA) and methyl methacrylate (MMA) via atom transfer radical polymerization (ATRP). A series of block copolymers, PEHA-block-PMMA(AB diblock) and PMMA-block-PEHA-block-PMMA(ABA triblock) were prepared via ATRP at 90 °C using CuBr as catalyst in combination with N,N,N',N″,N″-pentamethyl diethylenetriamine (PMDETA) as ligand and acetone as additive. The chemical structure of the macroinitiators and molar composition of block copolymers were characterized by (1)H NMR analysis, and molecular weights of the polymers were analyzed by GPC analysis. DSC analysis showed two glass transition temperatures (T(g)), indicating formation of two domains, which was corroborated by AFM analysis. Small-angle X-ray scattering (SAXS) analysis of AB and ABA block copolymers showed scattering behavior inside the measuring limits indicating nanophase separation. However, SAXS pattern of AB diblock copolymers indicated general phase separation only, whereas for ABA triblock copolymer an ordered or mixed morphology could be deduced, which is assumed to be the reason for the better mechanical properties achieved with ABA block copolymers than with the AB analogues.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylates / chemistry*
  • Biocompatible Materials / chemistry*
  • Calorimetry, Differential Scanning / methods
  • Chromatography, Gas / methods
  • Hot Temperature
  • Magnetic Resonance Spectroscopy / methods
  • Microscopy, Atomic Force / methods
  • Polymers / chemistry
  • Polymethyl Methacrylate / chemistry*
  • Scattering, Radiation
  • Scattering, Small Angle
  • Stress, Mechanical
  • Temperature
  • Tensile Strength
  • X-Rays

Substances

  • Acrylates
  • Biocompatible Materials
  • Polymers
  • Polymethyl Methacrylate
  • 2-ethylhexyl acrylate